Apparatus for treating foods



Nov. 5, 1935. G. GRINDROD APPARATUS FOR TREATING FOODS Original FiledAug. 6, 1927 RA m m m ATTORNEYS Patented Nov. 5, 1935 UNITED" STATESAPPARATUS FOR TREATING FOODS George Grindrod, Oconomowoc, Wis., assignorto Grindrod Process Corporation, Waukesha, Wis., a' corporation ofWisconsin Original application August 6, 1927, Serial No.

Divided and this application December 8, 1928, Serial No. 324,768.Renewed January 26, 1935 13 Claims;

into Patent No. 1,819,023 for a process of treating foods.

Sterilization-is destruction of living organisms, including spores. Itnecessarily involves the destruction of all living cells capable ofperforming life functions, particularly reproduction.

Heretofore, the principal agencies relied upon to effect sterilizationwere heat, life destroying chemicals and oxygen extracting and excludingagencies, the latter being, however, impractical for various reasons, asa commercial method where complete sterilization is required. The use ofchemicals for the sterilization of food. products is also not generallyavailable in the treatment of foods and therefore the prevailing methodof sterilizing foods is the thermal method, i. e.that of subjecting thematerial to a temperature suflicient to destroy all life within a givenperiod of time.

The thermal method has well recognized disadvantages due principally tothe fact that the character, flavor and composition of the food isusually altered. In the sterilization of milk by the thermal method,the. fat globules tend to break down and the albumen tends to coagulate.The customary practice is to raise the temperature of the food to asterilizing temperature and maintain it at that temperature for aboutthirty minutes without materially increasing it beyond the degreenecessary to complete the process within that period, although it haslong been known that the process can be accelerated by increasing thetemperature-in cases where the nature of the food is such that highertemperatures may be employed without destroying or impairing the valueof the product. But in the treatment of milk and allied food products,the time required to heat the food to the higher temperature, plus thetime required 'to again cool it to a point where the deterioration inquality and flavor will be arrested, has been found to be of suchduration as to preclude the use of the higher temperatures for suchpurposes. Therefore the moderate temperatures, requiring an interval ofabout thirty minutes to complete th process, are usually employed.

The problems indicated in the foregoing state- 'ment of prior artpractice have caused me to changes in environment, the power ofadaptation seek other methods of sterilization in the practice of which,the quality, characteristics and flavor of the food will be less subjectto change or impairment.

My experiments have led me to believe that steam particles moving athigh velocity into material under relatively low pressure, may destroyliving cells by friction and searing efiects as well as by impact andheat;

By the process and apparatus herein disclosed I employ such highvelocity steam jets to kill micro organisms present in-the materialbeing treated.

Biologists have pointed out that while all forms 'of life have certaindegrees of adaptability to is subject to limitations both as to timeallowed for such adaptation and the degree of change required to meetthe new environment. For example, a human being can survive changes inatmospheric pressure to only a very limited degree, if the changes arerapid, but to a much greater degree if the rate of change is slow enoughto permit the human organism to adapt itself to such changes as theyprogress. I have found by experiment that bacterial life may readilybecome inured, (adapted). to high temperatures, which, if appliedsuddenly in a first instance, would destroy such life.

I have therefore been led to experiment with changes other than heat inthe environment of bacterial life, and my experience has further led meto believe that it is possible to subject living cells and bacterialorganisms to pressure and heat changes, both external and internal, ofsuch a character as to require greater tenacity and resiliency, or powerof resistance, than that possessed by the walls of any existing livingcell or cellular tissues. My experiments also lead me to believe thatwhile living tissue responds readily by expansion and contraction togradual .pressure changes, it readily ruptures if subjected to pressureand heat changes calling for a more rapid expansion or contraction thanis required under the ordinary conditions to which such organisms areaccustomed. Further, I have discovered that impactive pressures may beapplied to small particles of material in such a manner that a singleinstantaneous application of such pressure, followed by a violentinternal expansive reaction, may be relied upon to completely exter- 5ominate all life in such particle.

It is therefore an object of thisinvention to provide apparatus forsubjecting foods such as milk and other materials capable of minutesubdivision, to violent pressure changes and reacli? denness andviolence capableof causing a rapid rise of internal temperature, with aconsequent violent expansive reaction, the heat rise within the livingcell being probably greater, and a high temperature more instantlydeveloped than in the surrounding media, and greater than it is possibleto attain by the heating agency externally applied during the sameinstant of time,"

for the reason that the heat of compression is added to the heatabsorbed from the surrounding media.

It is a further object of my invention to devise apparatus forsterilization by pressure change, in which each particle of materialand, as nearly as possible, each living cell therein, may be segregatedand directly exposed to the cell destroying pressure and each livingcell or organized group of cells destroyed in a single application ofsuch pressure, or a single momentary exposure to such pressures and thetemperature incident to such pressures and the means for applying them.Also I propose to envelop the segregated particles in a rapidly movingstream of hot steam or gas whereby successive particles of the heatingmedium are brought into contact with the particle to be heated. Also Ipropose to provide apparatus for effecting transfer of. heat from thesteam to the material being treated at a maximum rate.

It is my further object to provide apparatus capable of carrying out thesteam treatment process, hereinbefore described, in a continuous mannerwhereby sterilizing and other results obtained may all be accentuatedbeyond anything heretofore accomplished in those particulars. Further,it is my opinion that the time interval during which the material isexposed to destructive temperature conditions, may be greatly reducedand changes in chemical composition, flavor .and other characteristicsof the material may be more completely avoided by my new apparatus.

With reference to the preferred form or embodiment of my apparatus, itmay be stated that objects of this invention are to deliver material inthe form of a film or thin layer across the paths of a group of minutesteam jets in such a manner that the material comprising the film istreated by the steam jets and is carried with the steam through apassage into a chamber from which the material may be continuouslydelivered; to provide for collecting and continuously delivering thematerial so treated under conditions which permit a degree of thermalsterilization, when desired, without interruption in the continuity ofthe process or in the continuous delivery of the sterilized material; toprovide for an automatic regulation of such delivery for the purpose oftemperature and pressure control; to provide for the utilization of aportion of the steam to prolong the maintenance of thermal sterilizationin the material subsequent to its exposure to the treatment or impact ofthe previously mentioned particles by steam; to provide for a deliveryof the sterilized or, sterilizing material into a vacuum chamber in astream which is substantially continuously moving but in which themovement may be regulated by brief interruption or otherwise in a mannerto maintain substantial uniformity in the thermal treatment of all theparticles of the material and to finally 5 deliver the same into areservoir in a thoroughly sterilized homogeneous condition andsubstantially in its natural condition except for increased dispersionand the absence of living organisms.

In the accompanying drawing:

Figure-1 illustrates a preferred form of apparatus for carrying out myimproved process, the milk containers or chambers other than the finalreservoir being illustrated in vertical section and the piping ondcontrolling valves being illustrated conventionally.

Figure 2 is an enlarged fragmentary sectional view of one of the nozzlesshowing the means for twisting the jet. I

Like parts are identified by the same reference characters in bothviews.

' preferably has the general form of an inverted bell, capped by agenerally horizontal wall I, above which a similar wall I5 is supportedby a 2 ring l6 which, with the walls H and i5, forms a chamber orcompartment l3. A concavo convex cap wall I! has its outer margin boltedto the wall I5 and forms with the latter a steam chamber above thechamber I3. The material is conveyed by the pipe ll upwardly in thechamber I 2 and through a central port in the horizontal wall orpartition wall It which forms the floor of the chamber l 3. The floor I4has an annular row of studs 22 extending upwardly and each stud 22 has avertical threaded opening, shown in Figure 2. Threaded into the openingsare nozzles l8 which provide communication between supply chamber l3 andthe receiving chamber l2. The top surfaces of the nozzles l8 are shownflush with the top surfaces of the studs 22. Each of the nozzles l8 hasa flange l to limit the extent to which the nozzles may be threaded intothe openings in the floor l4, so that the aforementioned surfaces may bebrought flush with each other.

' The lower end of the nozzle l8 may be provided with internal helicalrib 35 for a purpose hereinafter described.

Liquid material such as milk may be delivered into the chamber l3through the pipe H and allowed to flow radially across the floor llthereof, and its depth slightly exceeds the height of the upwardlyextending studs 22. As hereinafter explained, it will be allowed to flowacross the upper ends of the studs 22 in the form of a film, from whichparticles may be successively broken and driven through the nozzleapertures by steam jets in the manner hereinafter described.

The partition, (horizontal wall l5) which separates chamber I 3 fromchamber 28, is provided with an annular row of apertures, the axes ofwhich are alined with those of associated nozzle ports 20 in the floor Mof chamber I3. Preferably, the floor I5 is provided with downwardlyextending tubular studs 29 which form nozzles in registry with theapertures in the floor but of less diameter than the nozzle ports 20.The passages through the studs 29 are preferably made as I small as isreasonably practical, consistent with V partition wall.

the purpose of delivering steam at high velocity and sterilizingtemperature against the film of The gap between the lower ends of thenozzles 29 and the upper ends of the nozzle studs 22 determines thethickness of the fiim of milk or other material to be fed into thepath-of the steam jets. If the studs 22- are in an annular row as shownin Fig. 1 they may be connected in the form of a continuous orsubstantially continuous rib projecting upwardly from the surface of theIn the construction shown, it may be assumed that the apertures throughthe steam jet nozzles 29 are approximately 0.05 of an inch in diameter.The ports 20 are somewhat larger in diameter or capacity, but specificdimensions are not mentioned for the reason that exactness in thediameter of these passages is not required. They are merely made largeenough to reasonably allow the passage of the steam and to allowparticles of'milk or other material to pass freely through them, whileprobably separatingintoa non-supporting relation to each other. Thesepassages 20 are axially aligned with those of the steam jet nozzles 29.Any desired number of registering nozzles may be provided within thecapacity of the receiving chamber l2 and its outlet to handle thedelivered material.

.and driven into the chamber l2. One of the nozzle ports 20 isillustrated in the enlarged sectional view, Fig. 2, and shows a shortlength of helical blade 35 at the mouth of the nozzle for the purpose ofproducing a whirling spray or imparting to the jet a helical twist as itenters the chamber I 2. An outlet duct 40 leads from the bottom of thechamber l2 and has a capacity which is initially insuflicient to carryoff the liquid as rapidly as it isdelivered through the nozzle ports 20.The capacity of the duct 40 may be regulated by a gate valve 4!.cumulates in the chamber l2 some pressure develo'ps in this chamber, butin order to prevent the development of excess pressure and temperto bedelivered to the apparatus, it is possible to.

control both .temperature and pressure within the chamber l2, for byreducing the quantity of milk delivered, accumulation beyond a desiredlevel in the chamber l2 may be prevented and the more nearly empty thischamber becomes, the

greater will be the expansion of the steam and the consequent reductionoftemperature and pressure.

The object of allowing an accumulation of milk As the liquid ac-- orother material in the chamber I2 is partially to prevent the escape ofsteam through the outlet 40 but also to allow sterilizingtemperature tobe maintained in the chamber l2 so that the mate- \rial may be subjectedto a'degree of thermo- 5 sterilization for a short period following theinitial steam treatment when delivered to the nozzle ports 20. This maynot be essential, but I preferably employ this means for a supplementalthermo-sterilization as a matter of precaution. m

I have found that I increase the efliciency of my apparatus by makingeach steam jet of minimum practical size and multiplying the number ofthe nozzles and jets (the efficiency of the jet increases in .proportionto the reduction in its diameter as long as the jet nozzle remainseffective to deliver steam at the required velocity). My opinionregarding the reason for the increase in the efiiciency brought about byreducing the size of each jet to a minimum is that the destruction ofliving cell'sis largely, if not almost wholly, accomplished at thesurface of the jet wherethe impacts necessarily occur. The frictionaland searing contacts also occur at the surface of the jet for after theinertia of the particle of material or the living tissue or the livingcell has been overcome and the particle entrained within the jet, theeffect will be thermal and the principal difference in operation ascompared with ordinary methods of thermal sterilization will thenreside. in the fact that the particle maybe enveloped in steam at ahigher temperature than that employed for ordinary thermalsterilization, although for a much shorter period.

' It is further my opinion that before a particle of the materialcan beso entrained and carried along with the steam jet, the results ,ofimpact, friction, and the rapid heat transfer induced by the flowingsteam will have raised the temperature of that particle of material to apoint near- 40 ly, if not quite, equal to that of the steam, and therapidity of this rise in temperature is far beyond the power ofadaptation of living tissue or cell walls to withstand, especially whilethe cell walls are being subjected to the coincident strains. 15

With a steam jet 0.05 of an inch in diameter, the ratio of crosssectional area to circumference is 1:80, whereas in a larger jet, suchfor example as a jet 0.375 of an inch in diameter, the ratio of crosssectional area to circumference is only 1 to 10.56. An idealconditionwould be realized if it were practical to subject the milk to theaction' of a steam jet of not exceeding twice the diameter of abacterial spore, i. e., about four microns, upon a milk film ofsubstantially the 56 same thickness.

The object of preheating the material in the chamber I0 is to reducecondensation and utilize the heat of the steam most effectively, but itis not desirable to raise the temperature of milk 60 beyond 160 F. inthe chamber I!) if thermal chemical change is to be avoided as fully aspossible.

If desired, additional supplemental provision may be made for furtherthermo-sterilization. In the drawing, I have illustrated a secondarychamber 50 which receives the material from the pipe 40, the baflle 5|being employed to throw the material downwardly within this chambertoward the outlet 52 at the bottom thereof.- I have pro vided a fioat 53in this chamber which controls an outlet valve 54 whereby the materialin the chamber may be discharged whenever it accumulates to such anextent as to lift the float and whereby such discharge will be checkedwhenever the level of the material falls to such an extent that thefloat allows the valve to close.

Steam may be admitted to the chamber 50 directly from the pipe 32through the branch pipe 56, the flow of steam being regulated by thetemperature controller 51 with its associated diaphragm chamber 58 incontrol of the steam pipe valve 59.

The escape of steam from the chamber 50 may also be permitted through apipe 60 having a valve at 6| controlled by a diaphragm at 62 operated bythe temperature controller bulb 63.

The steam delivered through the pipe'60 may be conveyed by a pipe 64 toa coil 55 in the prewarming chamber l0, thereby supplying the heat forprewarming purposes.

In the construction shown, the chamber 50 discharges its liquid or othermaterial through a pipe or duct 10 into an expansion chamber H where abaiile 12 again directs it toward the bottom of this chamber. 'The pipe64 leads from the top of this chamber and allows a free and unobstructedescape of the steam to a condenser indicated at 13. Therefore, theinterior. of the chamber H may be without pressure, the degree of vacuumin the condenser extending thereto. The outlet 15 of the chamber H isprovided with a valve 16 controlled by a float 11 whereby the contentsof this chamber will be intermittently discharged through a pipe or duct18 into a reservoir or receiver 19 which may also be assumed to be undervacuum. The reservoir 19 mayalso be assumed to be located below thelevel of the chamber 1| whereby the liquid will flow into the reservoir19 by gravity.

The operation of the apparatus will be under--' stood from the foregoingdescription but it will be obvious that the structure may be modifiedalmost indefinitely without departing from the scope of the invention asclaimed. The terms and expressions contained in this specification andin the appended claims are used for the purposes of description and notof limitation and while I have shown a structure in which the materialis delivered through a series of chambers, I do not intend to indicatethat such a series of chambers is essential.

I am aware of the fact that materials have been subjected to the directaction of steam in an effort to sterilize such materials and thatpasteurization and partial sterilization has at times been accomplished,but for the purposes herein set forth, complete sterilization mayfrequently be essential and in order to accomplish completesterilization or in order to accomplish any degree of sterilizationinstantly it is necessary to do something more than to merely injectsteam in a haphazard fashion into the body of the liquid to be treated.In my former application Serial Number 734,566 which has matured intoPatent No. 1,714,597 I have described a batch method of treatingmaterials in which I employ high, velocity steam jets under conditionswhich cause such a. violent agitation of the material as to causesubstantially all particles to move into contact with steam jets atleast once during the course of the treatment and have thus effectedcomplete sterilization in such a brief interval as to avoid materialchemical and flavor change.

But in this application and that from which it is divided, I believe Iam first to disclose means for providing a continuous .process for thepresentation of material to high velocity steam Jets in a manner tosystematically subject to direct single or simultaneous impact, eachparticle, and each living organism, for direct contact and destruction,whereby, as to each particle the operation may be completed in a minimumperiod of time. i

I also believe that I am the first to provide for such direct contact ofthe steam with successive small particles of material at a velocitycapable of imparting destructive impacts to the organisms contained insuch particles, irrespective of actual contact of' the steam with eachcell and coupled with such a rapid change in temperature and internaltemperature and expansion as to make adaptation impossible and ensuredestruction of life within the liquid so treated.

I also believe that I am the first to provide for applying to particlesof material sudden pressures or impacts under conditions which not onlytend to rupture the cells by-the direct force applied thereto, but whichallow the particles to be forcibly separated and freed from the supportof 20 surrounding media while such force is overcoming their inertiaand. which therefore permit such violent internal reactive expansion.and to virtually explode unruptured or imperfectly ruptured cells.

In my former Patent No. 1,461,653, dated July 10, 1923, I have disclosedin Figure 11 of the drawing thereof multiple steam nozzles adapted tooperate on the principle of an atomizer to draw by suction liqui-formmaterial such as fats or milk, or a mixture of fats and milk, intotubular passages which are sufficiently large to serve as verticallydisposed cylindrical expansion chambers in which the particles of fatare first drawn by suction into an eddying atmosphere surrounding thejets of steam, and in which they gradually acquire momentum, becomingflnally entrained with the expanding jet of steam and driven through theoutlets of the expansion chambers in the form of a spray. Some slightthermal pasteurizing effects might be obtained if the expansion chamberswere made of considerable length, but no provision was made formaintaining a sterile atmosphere nor sterility in the body of liquid inthe receiving chamber.

But by the invention herein disclosed the film of material to be steamtreated is received between the horizontal surfaces of the ends of thesteam nozzles and the opposing ends of the receiving nozzles, as bestindicated in Figure 2. and the particles of milk are not drawn in bysuction but are fed directly into frictional contact with impactingparticles of steam before being permitted to acquire momentum in thedirection in which the steam is flowing and before the steam 56 has beenpermitted to expand and allow its high temperature or any materialportion of its velocity to become dissipated.

In this manner each minute particle of milk may be directly subjected toimpact of a particle 60 of steam having exceedingly high temperature anda cell rending velocity.

In the improved apparatus described in this application, the ports 20have a capacity substantially equal to or but little greater than theca- 55 pacity of the steam jet nozzles plus that required for the addedquantity of milk, and inasmuch as the particles of milk are impacted andinstantly driven through these ports 20 into the receiving chamber, theycan be subjected to an exceedingly 79 high momentary temperature anddriven into the receiving chamber without coagulation, whereas in thestructure disclosed in my said former patent, No. 1,461,653, thetemperature of the steam employed, the relative sizes of the steamnozzles,

.the upper ends of the inlet ducts, a superposed and the expansionchambers, and the structure and arrangement of the receiving chamber,all constitute part of an organization in which coagulation of theprotein in the steam treated material was sought in order to build upmolecular ag egates of coagulating albumen upon the fat nuclei.

By the structure herein disclosed I am enabled to not only continuouslycarry on the sterilization. of milk and similar materials by invokingthe impact principle disclosed in my said Patent No. 1,714,597, grantedupon a companion application, but I am also able to more uniformlyexpose every particle of the material to such impact and to subject itto' but one such exposure with the exceedingly high temperature incidentthereto. Also, I am able to maintain the temperature of the liquid inthe receiving chamber I! at an exceedingly low sterilizing temperature,just suflicient to ensure a sterile atmosphere in said chamber, and asthe proteins of the milk or other material have been dispersed andstabilized against coagulation, and as they also pass out of thereceiving chamber into the vacuum chamber within a very short period oftime, cooking can be very completely avoided and reinfection madeimpossible.

I claim:

l. Sterilizing apparatus comprising the combination with a receivingchamber having a top wall provided with nozzles extending into saidchamber, of means for distributing the material tobe sterilized in theform of afilm over said wall in a position to be projected through saidnozzles into said chamber and means for directing jets of steam at asterilizing temperature and Ya dispersing velocity against said filmatthe inlet ends of said nozzles to carry particles from the filmthrough said nozzles, and a receiving chamber provided with acontrollable outlet adapted to permit sterilizing temperatures,corresponding pressures and volume control within the chamber.

2. Sterilizing apparatus comprising the combination with a feedingchamber and associated receiving chamber for the material to besterilized, of a series of nozzles communicating between said chambers,steamports of less diameter than said nozzles and aligned therewith fordirecting jets of steam at a sterilizing temperature into said nozzles,means for feeding the material to be sterilized in thin filmstransversely into the paths of said steam jets, and controllable meansfor continuously discharging said material from the receiving chamberinto a vacuum chamber.

3. Sterilizing apparatus comprising the combination with a receivingchamber having multiple inlet ducts in its top and arr-outlet in itsbottom portion, of a feeding chamber enclosing the upper ends of theinlet ducts, a superposed steam chamber provided with nozzles axiallyaligned with said ducts but of less diameter, means for constricting theoutlet of the receiving chamber sufiiciently to allow a moderatepressure and low sterilizing temperature to build up in the receivingchamber before the outflow balances the inflow and means for maintaininga supply of liqui-form material in the feeding chamber at a level toflow in a thin layer into the paths of the steam jets. Y

4. Sterilizing apparatus comprising the combination with a receivingchamber having multiple inlet ducts in itstop and an outlet in itsbottom portion, of a. feeding chamber enclosing steam chamber providedwith nozzles axially aligned with said ducts but with nozzle aperturesof less diameter, and means for maintaining a supply of liqui-formmaterial in the feeding 5 chamber and for forcing it to flow in a thinlayer substantially horizontally into the paths of the steam jets, saidreceiving chamber being provided with temperature controlled means forregulating the rateof delivery to the feeding o chamber, and the size ofthe receiving chamber outlet being so proportioned to the total capacityof the inlets as toprovide both temperature and pressure regulation inthe receiving chamber by said regulation of the rate of delivery. 15

5. Sterilizing apparatus comprising the combination with a feedingchamber and associated receiving chamber for the material to besterilized, of a series of nozzles communicating between said chambers,steam nozzles of less ca- 20 pacity than the first. mentioned nozzlesand disposed for directing jets of steam into said first mentionednozzles, means for feeding the material to be sterilized in minuteparticles transversely into the paths of said steam jets, and 25 .meansfor continuously discharging said matethe inlet ends of whichlatternozzles extend up- 35 wardly from the last named wall into closeproximity to the outlet ends of the steam nozzles, the diameters of saidaligned nozzles being so proportioned to the diameters of the steam jetnozzles as to allow particles of material to be fed directly alongtransverse lines into positions for frictional impactive contacttherewith by particles of steam moving at sufficient relative speed todestroy living cells by impact, heat, and frictional effects and tostabilize proteins by 5 persion, the opposing surfaces of said nozzlesbeing substantially parallel in planes substantially. perpendicular tothe axes of the nozzles, and a receiving chamber, a valve controlledoutlet in said receiving chamber adapted to maintain 50 therein asterilizing temperature.

7. Apparatus for sterilizing milk and other materials, comprising thecombination with a source of steamsupply, of a nozzle adapted to deliverthe steam from the nozzle at a high sterilizing temperature and celldestroying velocity, means for feeding liquid material in the form of athin film substantially transversely into frictional and impactreceiving contact of its particles with the steam, a receiving nozzle 60for the steam and liquid material so impacted having its inlet inregistration with and spaced from theoutlet of the steam nozzle, and areceiving chamber at the delivery end of the receiving nozzle having anoutlet in its bottom portion 65 and otherwise closed to allow a sterileatmosphere to be maintained therein.

8. Apparatus for sterilizing milk and other ,materials consisting in thecombination with a steam chamber having a wall provided with noz-Hm zlesfor delivery of steam at high temperature and velocity, 2. secondchamber provided with means for feeding the material to be treated intofrictional contact with said steam jets and uniformly, as tosubstantially all particles of such 75 material, for dispersing impactsof particles of steam upon the particles oi materials, and a receivingchamber provided with inlet passages aligned with said steam nozzles andadapted to permit delivery of the impacted material from the secondchamber into the receiving chamber, said receiving chamber being adaptedto allow a sterilizing temperature to be maintained therein and having avalve controlled bottom outlet connected with a vacuum chamber.

9. In a sterilizing apparatus of the described class, the combinationwith a steam :Iet nozzle, of an aligned receiving nozzle of slightlygreater diameter having its inlet end in proximity to the outlet end ofthe steam nozzle, and provided with helical bailies in its outlet endportion.

10. Apparatus for continuously sterilizing liqui-form materials,comprising the-combination with a steam chamber, oi. a set of steamnozzles adapted to deliver steam from said chamber at a sterilizingtemperature and cell rupturing velocity, means for continuously feedinga thin film-like layer of liqui-form material across the path of thesteam in positions to be impacted and frictionally dispersed thereby,and means for controlling the passage of the material into a sterilecooling chamber while protecting it from recontamination.

11. A chamber having an inlet port and adapted to be kept sterile, incombination with an injecting nozzle associated with the inlet port,means for delivering to the nozzle an elastic fluid at a sterilizingtemperature, and means for feeding a film of liqui-iorm materialtransversely into the path of the jet delivered through said nozzle tobe driven by the jet through said inlet a port, said chamber having avalved outlet adapted to regulate the pressure within said chamber andto regulate passage of the contents there- 5 013 said steam jet nozzle.

13. Apparatus for sterilizing milk and other materials, comprising thecombination with a source of steam supply of a nozzle adapted to 15deliver steam therefrom at a high velocity, means for feeding liquiformmaterial at a uniform rate and in the form of a film substantiallytransversely into frictional and impact contact with the steam jets, areceiving nozzle for the steam and liquid material so impacted, theinner diameter of the receiving end of the receiving nozzle being lessthan the outer diameter of the delivery end of the associated steamnozzle, and the receiving end of said receiving nozzle being separatedfrom the delivery end of its associated steam nozzle by a distanceequivalent to the thickness of the film, and a receiving chamber at thedelivery end of the receiving nozzle having an outlet in its bottomportion and otherwise closed to allow a sterile atmosphere to bemaintained therein.

GEORGE GRINDROD.

